High pressure washers are useful for cleaning all manner of objects. Although there are many types of high pressure washing systems, a typical system utilizes an engine that powers a high pressure pump. The pump is connected to a water source such as a low pressure hose, and the output of the pump is a high pressure line having a triggered wand. The wand has a nozzle or orifice through which high pressure water is sprayed. Typically, the engine and the high pressure pump are mounted onto a wheeled chassis so that they may be easily moved. Both the low pressure source hose and the high pressure output hose are relatively long so that a relatively large area can be accessed for washing without having to move the engine and pump, which tend to be somewhat cumbersome.
There are high pressure washing systems designed specifically for cleaning flat surfaces. These units use a wheeled stand that houses a rotating wand that is fitted with nozzles. The high pressure water hose from the pump is connected to the handle of the wheeled stand and the unit is moved across the surface that is to be cleaned.
A typical problem encountered with pressure washers is that the water is sprayed at high enough pressure that it can damage the surface that is being washed. These damaging effects can be alleviated to some extent by careful operator use—making sure that the spray stream is kept continually moving to avoid direct high pressure spray for a prolonged period on one spot. Another solution is to use a pressure control valve on the high pressure side of the system to regulate the spray pressure and to thus avoid damage to the surface being cleaned. Neither system is infallible, however, as anyone who has used a pressure washer recognizes. As just one example of the damage that pressure washing can cause, wood may easily be stripped from decking if the pressure washer is improperly used.
The problems caused by pressure washers are particularly acute where the surface that is being washed is relatively easily damaged. For example, flat surfaces that are painted or coated, such as tennis courts, may easily be damaged by improper use of a pressure washer. When the washing is accomplished by using a pressure washer fitted by a wand, not only is there a real possibility of damage, but functional washing of the entire surface is spotty since it is difficult to apply even coverage when using a hand wand.
There is a need therefore for improved high pressure washing systems, and particularly systems designed for washing flat surfaces.